This invention relates to polymeric ionic conduction and more particularly to polymeric ionic conduction in electrolytes or separators for electrochemical processes and devices.
In a wide variety of electrochemical applications, it is desirable to employ solid-state electrolytes having preselected ionic conductivities at ambient temperatures. Solid electrolytes having this characteristic are generally prepared by complexing ionic salts with polymers such as poly(ethyleneoxide) and poly(ethyleneimine). These electrolytes have low ionic conductivities at room temperatures because of the formation of crystallites. In addition the ambient temperature conductivities are low because phase separation and material deformation take place at temperatures in the range of 60.degree.-80.degree. C.
Another type of solid polymeric electrolyte is derived from proton conducting materials such as polystyrene sulfonic acid, polyperfluorosulfonic acid, and poly-2-acrylamido-2-methylpropane sulfonic acid. Protonic conductivity associated with these materials requires the presence of small amounts of water. This limits the reliability and utility of such conductivity, besides being corrosive in nature due to the presence of moisture.
Accordingly, it is an object of the invention to provide solid-state ion conducting electrolytes which can operate in a relatively wide temperature range extending from below 0.degree. C. to as low as -10, and above 100 to as high as 200.degree. C. A related object is to realize such electrolytes with conductivities which are not limited by material phase changes or absorbed molecules of water or solvent.
Another object of the invention to provide amorphous polymeric ionic conductors with improved conductivity and stability for electrochemical processes over a wide temperature range.
A further object of the invention is to provide polymeric selective ionic conductors in the form of flexible, non-brittle, and free standing thin films.
Yet another object of the invention is to provide simple processes for the production of polymeric ion conductors which are moldable, and can be coated or laminated to general substrates in transparent or opaque forms.